Originally Posted by TomHuffman
The only objective measurement for clipping is a dramatic drop-off in gamma at 90%.
How dramatic are we talking about? I also have this frustration with Gamma.
Hello. What is one of the best ways to go about doing gamma. I use chromapure with a id3 pro calibrated by Tom Huffman. Last night I did multiple tweaks to the gamma one by one then measure adjust, repeat....Everytime I noticed that even when using the Gamma module with the 100% white value in place and setting my gamma at 2.22 that when I take a post greyscale run my gamma in the 90% white drops to 2.16. 80% and 70% drop as well. I have done multiple adjustments and then post runs but the gamma still drops once a new white value is calculated from the post run. What I am trying to get at is what is the best approach in calibrating the gamma when you adjust one interval but then it could effect another. Say adjust 90 and then 80 then check 90? any tips to get it more linear and near target specially at 70, 80, 90 % white. It's a samsung d6500 plasma.
This is a reply from a message exchange with Micheal Chen.
Gamma is always calculated based on what 100 is. If you get it perfect in the module, it gets messed up in the post because the program wants an all new read of 100. Is this a bug?
What you can do is forget about the module and just do gamma in the post cal page. This one you know the reading will stick ... until you take another 100 reading of course.
Add to that, sometimes the formulas in one module get messed up a bit in another module. Calman has the same issues. Numbers don't translate the same when generating a report.
Try this first.
Gamma ... I like to set 100 first .. then get 50 right ... then 60 ... then 40 ...then 70 ... then 30 ...work out from the middle. Some TVs say start at 100 and work down ... 90 80 70 ... so forth ...